21224201 has 4 divisors (see below), whose sum is σ = 21956100. Its totient is φ = 20492304.

The previous prime is 21224191. The next prime is 21224207. The reversal of 21224201 is 10242212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4414201 + 16810000 = 2101^2 + 4100^2 .

It is a cyclic number.

It is not a de Polignac number, because 21224201 - 2²² = 17029897 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21224207) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 365906 + ... + 365963.

It is an arithmetic number, because the mean of its divisors is an integer number (5489025).

Almost surely, 2^21224201 is an apocalyptic number.

It is an amenable number.

21224201 is a deficient number, since it is larger than the sum of its proper divisors (731899).

21224201 is an equidigital number, since it uses as much as digits as its factorization.

21224201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 731898.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21224201 is about 4606.9730843581. The cubic root of 21224201 is about 276.8707751752.

Adding to 21224201 its reverse (10242212), we get a palindrome (31466413).

The spelling of 21224201 in words is "twenty-one million, two hundred twenty-four thousand, two hundred one".